The present invention relates to an alcohol burner and, more particularly, to a unit that can be used as an insert in fireplace or as a stand-alone unit and, more particularly, to an alcohol burner that uses liquid alcohol as a fuel source.
Primary factors that determine suitability of alternate methods of producing fire in the home for warmth and aesthetic ambience include venting abilities and safety. The first critical decision that a consumer makes when choosing a type of home fire product is the cost of installation and whether there is an existing vented area in the home. The cost of installation is the first step. Chimneys for exhausting unfriendly fuels (gas, wood) are expensive to install and maintain. Installation of vents/chimneys is not always possible/practical in all types of dwellings (older homes, apartments, loft conversions, etc.). Many parts of the country now prohibit log fire chimney operation due to fire hazard and pollution concerns. Municipal standards and building code requirements are becoming increasingly difficult and costly to meet. Some newer gas fire models use sophisticated internal air filtering and Cot detection equipment to preclude the need for exhaust chimney, but these solutions are still quite expensive to install.
Additionally, the cost of operation needs to be considered. There is no doubt that for high volume home heat production via a live fire feature, that natural gas is the cheapest per Btu hour. However, for all fuels that require ventilation (gas, wood pellets, logs, etc.), it is important to factor in heat energy lost through venting. Also, fixed location fires often lead to surplus heating being created in one area of the dwelling in order to facilitate heat spilling over into the desired area of the residence. Therefore in many instances, the use of a fuel such as alcohol, that is more expensive per BTU of energy—can actually prove to be comparatively affordable to use in certain home use situations. Because alcohol is a clean burning, ventless fuel, it cannot lose heat due to chimney venting—and it can be used in the precise location where warmth is desired by the user which ensures direct benefit of heat energy produced. Because portable alcohol fires can be quickly turned on and off and many can be adjusted for variable heat settings, they can be an excellent secondary source of direct warmth in conjunction with a larger heating system such as central heating/forced air supplied by a home furnace. A typical user can set the furnace thermostat lower (thereby achieving significant savings on the primary heating bill) and then use room specific portable alcohol heaters—and the blended result can be a lower total heating costs as compared with furnace heating alone, or as compared with furnace heating used in conjunction with a gas, log or pellet fire. However, if a user does not have a primary heat source in the home, alcohol fires would not be an affordable primary source of home heating.
Still another consideration is whether to select portable versus fixed location for the fire burner. Apart from the above mentioned considerable cost factors associated with installing fixed location vented fires, there is a strong usage preference by many users in favor of portable fire features that can be moved to different areas of the dwelling. As single portable fire feature can act as living room fire, bedroom fire, sit by the side of bathtub or be moved to an outdoor deck or garden setting. This creates great versatility in terms of both the aesthetic ambience created by the live flame, and also in terms of delivering immediate warmth when and where desired. However, it should be noted that this portability feature depends greatly on a) the safety features of the portable burner unit and b) the suitability of the fuel it uses—in terms of exhaust, and also ease of handling in a home environment. Liquid alcohol is far superior to any other fuel type for portability as it is the only fuel that addresses all of these concerns.
Environmental factors when choosing a home product are increasingly important. Liquid alcohol is the hands-down winner against all other possible fuel types that can be used for producing natural home fire.
Conventional wood burning fireplaces are becoming a thing of the past. When incorrectly constructed, such fireplaces produce smoke in a living space. Even if correctly built, conventional fireplaces cause chimney creosote buildup, which must be regularly removed. Ashes resulting from burning of wood often spill into the living space, requiring the home owner to clean not only the fireplace but also the surrounding areas and furniture. To solve these problems, the industry developed various alternatives, such as fixed supply line natural gas fireplaces, propane fueled fire pits, gel pot portable fire features, gel fuel fireplace burners, and poorly designed alcohol fire burners. Such conventional solutions suffer from many shortcomings. It should be noted that the heat produced by alcohol in gel and liquid form is roughly the same in both forms of the fuel—when flame size is comparable. Gas fires produce heat dependent on the size of the burner, the capacity of the supply line and the adjustment of the control valve. A log fire can produce anywhere between 500 btu and 50,000 btu for a raging 6 log fire, but most normal users find 10,000-20,000 btu comfortable for a sustained period of time. A good portion of this energy is lost through the chimney exhaust. Gas fireplaces can be turned down as low as 3,500 btu and many can be turned up as high as 35,000 to 45,000 btu, but this is too much heat for most living rooms, so unless there is a heat ducting system to share the heat with other parts of the house, most living room settings would settle for around 15,000 btu (and again, lose some of this up the chimney).
All of the above factors combine to inform the basic distinction between fixed and portable fire features. Once a purchaser has determined that they desire a portable fire feature that can be used indoors, the field of possibilities is narrowed to just gel alcohol and liquid alcohol used by indoor alcohol burners, and even more narrowly to ethyl alcohol and isopropyl alcohol. Ethyl alcohol is made from food crops such as corn or sugar cane. Isopropyl alcohol is very commonly available—but not nearly as well suited for home fires because of its potentially harmful exhaust. Isopropyl alcohol is made from by-products of refined fossil fuels (natural gas or oil) and this is why it releases higher levels of Co2 than ethyl alcohol. It also produces some Carbon Monoxide and also other noxious emissions—which is why it is not favored for humans to breath its exhaust indoors (ethyl alcohol produces no Carbon Monoxide). Gel alcohol fire fuel is mainly made from isopropyl alcohol—and as such, it is better suited either to outdoor use or for use in vented traditional fireplaces that have chimneys (this is the way many of the common cartridge gel alcohol fire systems are marketed—as fireplace replacements for vented hearths).
Liquid Isopropyl alcohol (aka rubbing alcohol) is widely available at pharmacies and hardware stores—and it will burn (producing a blue flame)—but indoor fire users complain of headaches and drowsiness when exposed to it for even a moderate period of time.
Methyl alcohol (aka methylated spirits) is widely available; it is made from wood by-products. It produces a flame similar to ethyl alcohol, but the primary reason it is not recommended for fireplaces is that it is highly poisonous when consumed orally—and so having it in the home environment is a greater risk compared with ethyl alcohol—and since ethyl alcohol is cleaner and greener, there is no reason to consider the less common methyl alcohol as a fireplace fuel.
Gel alcohol is generally considered more hazardous than liquid because it is prone to splatter under certain circumstances, and when it does, it sticks to human skin and is difficult to extinguish. The U.S. Consumer Product safety Commission (CPSC) recently announced a general recall for all pourable gel alcohol fuels intended for use with fireplace type products because of the high likelihood of consumer misuse—when pouring the gel into a hot container or onto a flame that the user thought had already been extinguished, splatter and fire hazard can easily result. It is important to note that this recall does not pertain to canister formats of gel fuel. Additionally, gel fuel uses emulsifiers and other additives that result in a sooty crust by-product of burning—and this is messy and unsightly in addition to creating an odor that many find to be unpleasant. Conversely, when liquid alcohol is burned, there is no soot, no residue, no crust and no odor.
Gel alcohol (isopropyl) can typically only be used indoors to create small “table top” fires—due to the exhaust it emits. Exhaust produced from a small can of gel alcohol is unpleasant, but in a good sized open area most people will not suffer ill effects. But for a larger fireplace type fire effect, gel alcohol should be limited to use in a vented fireplace hearth type setting.
As to the safety factor: the safety risks for other home fire fuel types are well known (gas fire places blow up houses and poison people in their sleep when they leak unburned gas, log fires cause chimney and roof fires, etc.). but once a user has determined that their needs are best met by a versatile, portable ventless fire, and once the issue of exhaust and environmental concerns have been considered (e.g. clean burning alcohol versus other, less clean fuels), the focus of selection should be the distinction between gel and liquid alcohol, and then between simple, rudimentary burner design for liquid alcohol versus sophisticated, advanced designs for alcohol burners. It was earlier perceived by many that gel alcohol would be easier for users to handle, and therefore safer than liquid alcohol. However, since being widely introduced to the marketplace, gel alcohol had much higher reported incidents of accidents. But the main factor is the propensity of gel to splatter when it comes in contact with a surface that is much hotter than the gel alcohol—and this is something that can happen as a result of consumer misuse. When accidents do happen with gel alcohol, they are particularly harmful to people because of the way hot gel alcohol can stick to human skin. It is now generally understood and accepted by the industry that liquid alcohol is much more stable and predictable and therefore safer when used in the right type of burner device.
It is worth noting that one of the advantages of many alcohol burners over other fire feature types, is that because they are compact and portable (and ventless) they can be installed in ways that make them much more visible to home users than ever before possible. The optimal application of a home fire is to provide and equal balance of cozy warmth with the visual stimulation of watching a flame dance. Most fireplaces do not afford a clear sightline to the fire from many vantage points. A hearth allows for only very limited viewing from the front side and often at a distance from where people are standing or sitting. A portable alcohol fire feature can usually be viewed from all four sides, and can be positions in an unlimited variety of positions in proximity to home user. This is probably one of the most important features that users cite as their reason to buy a portable fire feature over the other traditional alternatives. Until now, perceived safety was the main barrier to adoption by users who wanted to place a fire closer to their favorite places to spend time in their homes—but they were afraid to do so.
However, it should be noted that many early generation burners on the market which use liquid alcohol have important limitations in terms of their safety features.
A known alcohol fire burner is disclosed in U.S. Pat. No. 7,287,979 issued on Oct. 30, 2007 for “Burner for a heater.” This burner comprises a combustion chamber having a combustion zone for combusting the hydrocarbon liquid and at least one tank portion for containing an amount of the hydrocarbon liquid. Each tank portion is positioned adjacent the combustion zone and is arranged to feed the hydrocarbon liquid into the combustion zone. A combustion control is designed to control gas exchange of the combustion zone through a gas exchange opening of the combustion chamber, wherein the burner is arranged so that the fuel inlet opening is only fully open when the combustion control means closes at least a portion of the gas exchange opening of the combustion chamber. This design presents a typical solution of conventional alcohol burners; it is arranged for the combustion of ethanol or methylated spirits. The tank portions are filled with stainless steel wool which distributes heat and reduces likelihood of ignition in the tank portions and thereby reduces formation of air pockets within the hydrocarbon liquid. However, stainless steel wool has a limited absorption capability, making this type of burner hazardous. Additionally, this burner is likely to create large pockets of trapped alcohol vapor mixed with oxygen and allow these pockets to remain stored in compartments in the device—creating a vapor cloud that flares dramatically upon ignition. This can not only be frightening to consumers, it can lead to unexpected flashes of flame that can ignite clothing or other nearby materials.
One of the other known publications is U.S. application publication No. 20050178379 for “Alcohol gel fireplace burner,” which discloses a device for creating a fire display in a fireplace, which comprises a noncombustible logset having a substantially rectangular shape and having an internal cavity communicating with an opening on a top surface of the noncombustible logset, and a rectangular fuel cartridge located in the internal cavity of the noncombustible logset, where a top opening of the fuel cartridge is aligned with the opening in the top surface of the noncombustible logset. The burner of this application is likely to have the same disadvantages when using gel alcohol as other such burners.
Another patent document published under publication No. 20110070551 for “Burner using alcohol as fuel” discloses a device, which uses an absorbent material filling in the internal space of the container such that when the alcohol level decreases and the alcohol burner is in use, chance of backfire situation is greatly reduced. The alcohol burner of this application has a container, a tracking plate on top of the container, a top cap on top of the sliding plate and a sliding plate slideably situated on top of the tracking plate to selectively close/open an opening defined in the tracking plate. There is also provided a bottom plate with a grill securely attached to the bottom face of the bottom plate to fix position of the absorbent. Because the sliding plate is separated away from the grill by both the tracking plate and the bottom plate, sufficient space is provided to the sliding plate to ensure that even there is deformation in the bottom plate, movement of the sliding plate is not influenced. Also, due to the limitation of the absorbent to the alcohol, when the alcohol burner is moved from one place to another, the alcohol spilling is said to be obviated to the minimum. The absorbent in the container may be made of ceramic material or cotton.
The design of the burner according to publication No. 20110070551 suffers from several shortcomings: the flame is likely to be weak, prone to premature shut-off because of insufficient vapor production and absence of a heat-conducting medium like metal to conduct heat down into fiber. Also, the burner will be difficult to light since there are no vapor holes down in wool; the planar grill does not create a visual depth in the flame pattern; the ceramic fiber absorbent is too deep, preventing evaporation from the lower portions of the container. While this device may work satisfactorily in certain circumstances, there is still a need for an alcohol burner that eliminates all of the safety hazards (fuel spill, flash ignition hazard, etc.) associated with previous existing devices that are used for portable alcohol fire features.
The present invention contemplates elimination of disadvantages of the prior art and provision of a spill-proof portable alcohol burner with increased safety characteristics.